Assuming you already created a Instagram app, got a 1 hour token.
First you do something like this:
GET https://graph.instagram.com/access_token
?grant_type=ig_exchange_token
&client_secret={instagram-app-secret}
&access_token={short-lived-access-token}
This will give a 60 days access token
Source
Once you got the the long-lived token, you can make a GET requst from this endpoint: https://graph.instagram.com/me/media
Add the token:
../me/media?access_token={access-token}
You can add also these some of these fields:
.../me/media?fields=media_url,thumbnail_url, caption&access_token=access_token={access-token}
This should return a json file that include things you need to do the portfolio.
Keep in mind that the token lasts only for 60 days and you need to refeash it once this time is over:
See this for more information